My DD had the same type of poop you are describing for the first couple of months. I was concerned, as you are. I found it to be very green, slimy or almost mucous like. It looked like she had liquified grass in her diaper! It was not frothy though- which is good. I spoke with her paediatrician and he told me that it was completely normal- there is a wide variety of colour for EBF poop. As she got older it changed to a more yellow colour. (She is now 4 months, still EBF and it is still greenish sometimes, but mostly mustardy. There may be nothing at all wrong- but talk to your doctor to be sure.